Many of the large and medium sized arteries commonly affected by atherosclerosis are accessible to sources of energy such as ultrasound. The goals of this project are to develop a method of ultrasonic arteriography which can be used to visualize the arterial anatomy of arteries which are involved with atherosclerosis. With the techniques being developed it will be possible to identify and follow areas of narrowing. This technique will be useful in (1) establishing the site and extent of involvement; (2) study the patency of aorto-coronary grafts; (3) screen patients with Transient Ischemic Attacks, and (4) studying the long-term patency of bypass grafts in the limbs.